Escapement



Oct. 11, 1938. E, E. TALlAFERRO 2,133,216

ES CAPEMENT Filed March 7, 1936 Patented Oct. 11, 1938 UNITED STATES PATENT OFFICE i6 claims.

This invention relates to clocks and in particular to an improvement in the time escapement mechanism and has for its primary object the provision of an escape means for prolonging the life and for improving the time keeping qualities of pendulum type clocks.

Another object is the provision of a scape Wheel which improves the time keeping qualities of clocks employing less accurate forms of verge. For example, the recoil escapement used in the average mantel clock is recognized as not being as accurate as the dead beat escapement and it is an object of my invention to improve the accuracy of the recoil type of escapement while at the same time increasing the useful life of the clock and at almost no increase in the cost of manufacture.

Briefly speaking I carry out the above objects of my invention by staggering the teeth on the f2'0 scape wheel so that the contact with'the verge is spread over a much greater area than is possible with the teeth in one plane as used in the prior practice. By oppositely offsetting the successive teeth I prevent the active surfaces of the verge from being Worn and pitted in one spot and instead cause the Wear to be spread over as much of the locking and impulse faces as desired or as warranted by the expected life of the other mechanism in the clock. In other words, my invention brings the life of the escapement mechanism more in line with the life of the other parts of the clock and this is accomplished at a negligible cost and without changing the basic design of the parts. This will be appreciated by reference to the following specification and the attached drawing.

In the drawing:

Figure l is a front View showing a standard dead beat escapement altered in that the teeth of the scape wheel are bent 0r offset right and left.

Figure 2 is a sectional View of the mechanism shown in Figure 1 and taken on line 2-2.

Figure 3 is a diagrammatic layout showing the points of contact of the locking and impulse faces of the verge with the teeth as bent in Figures 1 and 2.

Figure 4 is similar to Figure 3 but showing a modification in Which a straight tooth remains between each two right and left teeth.

' Figure 5 is similar to Figure 3 but on half as large a scale showing a further modification in which the teeth appear to be sinusoidally arranged when the scape wheel is viewed edgewise.

Figure 6 is a perspective view of a modified scape wheel.

Figure l is a view similar to Figure 2 but showing the spread of the teeth as less than the width of the pallet.

Figure 8 is an edgewise view of a thin scape wheel having a sinusoidal Wave in the rim.

In Figures 1 and 2 the verge I0 and the scape wheel l2 are shown associated in the usual manner on their respective axes I4 and I6. The verge is of any well known shape having on both its receiving pallet R and on its discharge pallet D a locking face I8 and an impulse face 20, Altho I have shown a dead beat escapement this is purely for illustra-tive purposes as it will readily be appreciated that my invention is equally adapted to recoil type escapements commonly used in clocks, in fact it will probably have its greatest use in the recoil type.

In the preferred form of my invention the alternate teeth 22 are offset to the right of the plane of the scape Wheel (see Figure 2) while the other teeth 24 are oiset to the left of the plane whereby the successive teeth engage the surfaces of the verge in different spots as shown diagrammatically at 22 and 24 in Figure 3. Thus the wear on the verge in effect is reduced one-half with the result that the clock should keep running and keep accurate time twice as long as is now possible with clocks equipped with the present day scape where the teeth are all in one plane. As the individual teeth of the preferred form of the Wheel are viewed edgewise each tooth appears to have a bayonet shape as clearly shown in Figure 2. To facilitate the description, the front or working faces of the teeth will be called the active faces to distinguish them from the back and side faces of the teeth which are inactive in that they are never engaged by the verge. As usual with these types of escape wheels the front or active face of each tooth intersects the inactive back face 0n a line at the tooth point which line is substantially parallel to 'the wheel axis. The scape wheel shown in Figure '7 is almost exactly like that in Figure 2 except that the teeth 22 and 24 are not offset so far from the plane of the wheel and in fact the teeth engage overlapping surfaces on the pallets.

In order to further prolong the time keeping qualtities the teeth of the scape may be arranged, as diagrammatically indicated in Figure 4, with every third tooth 26 left in the plane of the wheel and with the teeth 32 and 34 offset to the right and left of the plane respectively. InA operation the staggered teeth of the wheel successively engage a face of the verge, for example the locking face on overlapping areas with the result that the total wearing surface is substantially three times that engaged by the in-line teeth of the normal escape wheel. A still further modification, indicated in Figure 5, consists in arranging the teeth 36 in what appears to be a sinusoidal line as the wheel is viewed edgewise so that the wearing surface extends continuously and almost entirely across the contact faces of the verge. This permits the use of a very thin scape in which the wave can be set in the wheel rim the teeth remaining straight. An edgewise View of such a wheel is shown in Figure 8 but the rim of the wheel illustrated in this figure is curved less than indicated in Figure 5 so that the total spread of the teeth 36 is only about double the width of a single tooth and is appreciably less than the width of the pallets indicated by the two broken lines l0l0.

A still further modification of' my invention, shown in Figure 6, consists in the use of a plurality of scape wheels for example, wheels 3l and 38 secured side by side on the same shaft 39. It will be seen that the teeth on each wheel are twice as far apart as required where a single wheel is used. This modication permits the use of present stock by merely cutting oi the alternate teeth from the wheels and then pressing two on each shaft in the usual manner but with the teeth of one falling between the teeth of the other. The front or pallet engaging faces of the teeth are shown in Figurel as being radial and some of the claims state that these faces are substantially radial but it is well understood by clock makers that the front faces are in fact almost invariably cut away or sloped backwardly from the tooth point to provide clearance for the verge as it swings in and out. My use of the term radial is merely to distinguish from those types of scape wheels in which the pallet engaging faces of the teeth are nearer tangential.

It will be obvious that in all modifications any number of successive teeth may be offset in one direction and the rest offset in the other direction but the successive staggered or zigzag arrangement is preferred as it gives a more balanced movement.

The scope of my invention also includes the method of repairing clocks bysetting the teeth to the right and left of the normal plane of the wheel or by setting the teeth in a zigzag or wavy line. This gives the clock a new lease on life and may well be worth thecost.

My invention should not be confused with those rare escapement mechanisms used primarily in watches and in which two sets of laterally spaced teeth are provided on the scape wheel, one set being used to impart power to only one pallet of the verge or balance to swing it in one direction and the other set being used to impart power through the other pallet to the verge to moveit in the opposite direction. In these rare types the pallets oscillate in spaced parallel paths. My invention is primarily for improving common escape wheels of the type in which each and every tooth imparts power to the verge inY both directions of oscillation of the verge. Stated in other words, each tooth engages the receiving p allet R' and each tooth likewise engages the impulse pallet D.

In some of the claims it is stated that the teeth lie in planes which of course is not strictly accurate because a plane has no thickness but this terminology is used to mean that the working portion ofthe teeth, i. e., the portion between the tip of the tooth and the point marking the depth of engagement by the pallet, lies between two parallel planes which planes are parallel tothe central plane of the wheel. In other words, the plane in which the tooth lies is assumed to have a thickness equal to the width of the front or active face of the tooth which face is normal to the central plane of the wheel. Some claims also state that the pallets of the verge oscillate in the same plane which is intended to meanv that the pallets are not oifset with respect to each other but are containd between the same two planes.

What I claim is:

l. A toothed escape wheel of the type disclosed having a set of outwardly pointing teeth, the end portion of said teeth being V-shaped in side vieW and each tooth having its front face intersecting its back face on a line substantially parallel to the wheel axis characterized by the end portion of some of said outwardly pointing teeth being laterally offset with respect to other of said outwardly pointing teeth.

2. In a pendulum clock escapement, a toothed escape wheel and a cooperating verge pivoted on spaced but substantially parallel axes, a plurality of the teeth of the wheel positioned to engag the same pallet of the verge as the wheel rotates, some of said plurality of teeth being out of alinement with respect to other of said plurality of teeth as the wheel is viewed edgewise thereby utilizing a total wearing surface on said pallet of the verge greater than that acted on by a single tooth.

3. An escape wheel having teeth projecting peripherally from 'the rim, thefactive face of each tooth being substantially radial, the working portion of some of said teeth being offset laterally with respect to the working portion of other of said teeth.

4. The method of making a scape wheel from a plurality of normal scape wheels which comprises removing certain teeth from said wheels and then fixing said wheels on a shaft with the remaining teeth in registry with the spaces left by the removed teeth. Y

5. A scapeV wheel comprising two scape wheels set side by side on a Shaft, the wheels having spaces due to alternate teeth in each wheel being absent and the wheels being positioned on the shaft with the teeth of each in registry with the spaces left by the missing teeth of the other.

6. A time escapement mechanism comprising a verge, a scape wheel having a plurality of teeth in the plane of the wheel, a plurality of teeth to one side of said plane and a plurality of teeth to the other side of said plane, the width of the contacting surfaces of the verge being substantially equal to the total spread of the teeth whereby the area of the wearing surfaces of the vergeV engaged by said teeth extends substantially across said surfaces and is greater than the wearing area of a single tooth.

'7. In a pendulum clock escapement, a verge and a cooperating toothed scape wheel veach tooth of which is adapted to impart power to the verge in both directions of oscillation, the verge having tooth engaging faces adapted to oscillate in the same plane, and certain teeth of the scape wheel being offset laterally with respect to other teeth whereby to engage said verge faces on areas different from the areas of the same faces engaged by said other teeth.

8. 'I'he device of claim 7 in which the oifset of the teeth is such that said areas overlap.

9. The device of claim 2 in Which some of the said non-alined teeth lie to one side of the central plane of the wheel and some of the teeth lie to the opposite side of said plane.

10. The device of claim 2 in which the rim of the Wheel is curved as the wheel is viewed edge- Wise.

11. The device of claim 2 in which some of the teeth lie in the central plane of the Wheel and some of the teeth lie to one side of said plane.

12. In a pendulum clock, an escapement comprising a verge of the type disclosed, a toothed scape Wheel in which the active faces of the teeth are substantially radial, characterized by the teeth being arranged in zigzag relation as the wheel is viewed edgewise whereby the total area of each Wearing surface on the verge is greater than that acted on by a single tooth.

13. A scape wheel for pendulum clocks, said Wheel having peripheral teeth of sharp V-shape, the active faces of which appear to project radially outward as the wheel is viewed axially but in which the active ends of some of said teeth are adapted to move in annular paths parallel to but different from the annular paths of the ends of other teeth and the plane of the Wheel.

14. A toothed scape wheel as described in claim 13 in which said teeth appear to be bayonet shaped as viewed edgewise.

15. In a clock escapement, a verge and a toothed scape Wheel, the verge having tooth engaging pallets adapted to oscillate in the same plane and each pallet adapted to engage each tooth of the Wheel, the active faces of said pallets being wider than the cooperating faces of the individual teeth of the scape wheel, certain teeth of the scape Wheel being arranged to engage said pallet faces on areas different from the areas engaged by other teeth of the wheel whereby increasing the Wearing area on said active faces.

16. A clock escapement comprising a verge of the dead beat type and a cooperating escape Wheel, said verge having a pair of pallets adapted to oscillate in a single plane parallel to the plane of the escape Wheel, and peripheral teeth on said wheel, each tooth adapted to engage each of said pallets, some of said teeth being out of alinement with respect to others as the wheel is viewed edgewise.

EDWARD E. TALIAFERRO. 

